1. Field
The downlink radio link quality in wireless mobile radio communication system can vary in time and in frequency due to the frequency selective multipath fading radio propagation environment. A user equipment (UE) can support the radio resource management of a Node B by monitoring the downlink radio link quality of the serving cell or cells during the connection in order to indicate if reliable enough communication is possible in downlink and in uplink. Thus, if downlink is not reliable enough for communication then uplink communication can also be shut down.
2. Description of the Related Art
Downlink radio quality is conventionally estimated in receivers based on both transmission power control and cell-specific reference signals. These signals are distributed to the whole system bandwidth by spreading in narrowband or wideband Code Division Multiple Access (CDMA) transmitter or by design in the Time Division Multiple Access (TDMA) transmitter and thus the post-detection Signal to Interference plus Noise Ratio (SINR) values are not frequency-selective due to the despreading or by design in the receiver. In other words, the interference is not frequency-selective due to the CDMA or TDMA signal used. There is no attempt made to average the SINR values in frequency across the system bandwidth in the conventional, for example, 3rd Generation (3G) receivers. Each radio link monitoring out-of-sync or in-sync decision in 3G is made by comparing the long term SINR estimate to the pre-defined Qout and Qin thresholds.